Vapor-phase corrosion inhibitor product

ABSTRACT

The present invention provides a corrosion inhibitor assembly or emission of vapor phase corrosion inhibitor compound inserted into a shipping/packaging container. The assembly has a pouch formed as an envelope of vapor porous surrounding sidewall defining an inner compartment of a fill material composed of an inert substrate with embedded corrosion-inhibitor emitting compounds. The substrate acts as a substantially inert carrier for the compounds, to avoid the need for friable solids or powders in the pouch, yet permit vapor flow of compounds though the sidewall to area outside the pouch.

TECHNICAL FIELD

The invention relates to products and methods for metal corrosion inhibition though vapor-phase corrosion inhibitor compounds emitted within a product package/container. More specifically, the present invention relates to vapor permeable envelope products that contain vapor-phase corrosion inhibitor compounds with a generally inert substrate.

BACKGROUND OF THE INVENTION

Corrosion inhibitor products are widely used in a number of applications, ranging from engine use to product packaging. One common form of corrosion inhibitor products is the use of vapor-phase inhibitor emitting compounds in product packaging, including compounds being incorporated into plastic packaging film, and small containers of vapor-phase corrosion inhibitor material that are placed into a shipping or packaging container for a product that may otherwise be susceptible to corrosion of the metal parts. Plastic film with corrosion inhibitor compounds is made by incorporating such compounds into low density polyethylene resin, which is extruded and formed into plastic sheet stock that is used as a wrap or as envelopes of plastic packaging for the metal being protected from corrosion. Other similar products and methods include the use of a coating on a portion of the packaging material, use of tablets of the corrosion inhibitor compound, use of an absorbent pad treated with corrosion inhibitor compounds and taped to the inside of a shipping container, use of cups containing the compound with a vapor permeable top cover, and use of vapor-permeable envelopes containing powdered solid of the corrosion inhibitor compound, such as is described in U.S. Pat. No. 4,973,448. The commonly used products and methods, however, are susceptible to deficiencies or draw backs that make them less than optimal in certain applications, and tend to be less adaptable for use with different packaging contents and differing sizes of containers. Most notably, many of the products and methods for such corrosion inhibitor vapor in packaging utilize differing types of compounds and materials, and are therefore not readily compatible in manufacture and use. For example, the use of plastic film incorporating corrosion inhibitor compounds is distinct in manufacturing features and components from the use of pouches of powdered solid as described in U.S. Pat. No. 4,973,448. Thus, separate manufacturing processes must be employed, lacking cost savings associated with compatible manufacturing processes. Further, in the case of products that include powder or powder-like appearance of the corrosion inhibitor compound, including that which is described in the above-referenced patent, use of such powdered substance in packaging is particularly disadvantageous due to risk of powdered material leaking from the envelope. This risk is amplified due to possible alarm to persons perceiving a danger of powder within a shipping container.

Accordingly, there is a need for a reliable manner of providing a volatile vapor-phase corrosion inhibitor compound in a product packaging without use of powder that may be perceived as a threat, or otherwise detracting away from the delivery of a clean non-corroded product. Further, there is a need for a method of manufacturing a corrosion inhibitor product that may be integrated with the manufacture of other types of corrosion inhibitor emitting products, such as plastic films, and providing the versatility of having a pre-determined amount of compounds such that incremental numbers of products may be used, depending on the size of the container and the resulting desired amount of the compounds.

The present invention is provided to solve the problems discussed above and other problems, and to provide advantages and aspects not provided by prior products and methods of this type. A full discussion of the features and advantages of the present invention is deferred to the following detailed description, which proceeds with reference to the accompanying drawings.

SUMMARY OF THE INVENTION

The present invention provides a corrosion inhibitor assembly for emission of vapor phase corrosion inhibitor compound inserted into a shipping or packaging container. The assembly provides an outer encasement envelope constructed of sheet stock having vapor porous properties for permitting vapor to pass into and out of the envelope. The envelope is sealed to form an inner chamber with at least a portion of the porous sheet stock configured to provide vapor passage through the sheet stock material, and includes a body of generally inert substrate material with embedded vapor phase corrosion inhibiting compound.

The present invention further provides a pouch made up of a synthetic outer encasement envelope containing a non-frangible and non-friable fill material of a base medium with the corrosion inhibiting compound, such that the envelope contents is in the form of a visible solid that is generally absent of visible powder and not readily crushed into a powdered form. Further, the present invention provides a method of providing corrosion inhibiting compounds in the vapor of a packaging for a product, including the steps of providing an encasement envelope constructed of vapor porous sheet stock and having at least one fill opening for receiving a fill material having an inert substrate material with an incorporated corrosion inhibiting compound that is not readily frangible into powder form.

Other features and advantages of the invention will be apparent from the following specification taken in conjunction with the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

To understand the present invention, it will now be described by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a product package container, depicting a product inside the container and having a partial cut-away to reveal a corrosion inhibitor assembly inside the container according to the present invention;

FIG. 2 is a perspective view of an envelope according to an embodiment of the present invention;

FIG. 3 is a cross-section view of the envelope shown in FIG. 2, taken along lines 3-3, depicting fill material within the envelope according to an embodiment of the present invention;

FIG. 4 is a side view of a sampling of the fill material as depicted in FIG. 3, according to an embodiment of the present invention;

FIG. 5 is a cross-section view of a resin pellet type of fill material of the invention depicted in FIGS. 3 and 4;

FIG. 6 is an elevated perspective view of an alternative embodiment of the envelope shown in FIGS. 1-3, with a portion of the vapor permeable outer material cut away;

FIG. 7 is an elevated view of another alternative embodiment of the assembly, having a pad within the envelope and depicted with a portion of the encasement material cut away;

FIG. 8 is an elevated view of another alternative embodiment of the assembly, having at least one body (shown as a block) located in the envelope and a portion of the outer encasement material cut away; and,

FIG. 9 is an elevated perspective view of the body shown within the envelope in FIG. 8.

DETAILED DESCRIPTION

While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated.

The present invention is an assembly 14 and method for providing vapor phase corrosion inhibitor compounds in a container 10 such as may be used for shipping or storing a product 12 with metal parts. The assembly 14 includes an envelope assembly 16 that is formed of a sheet stock of a vapor permeable material 18, such as a sheet stock formed of synthetic fiber. Typical types of such fiber material include sheet stock formed of polyolefin material, and may be formed as a pouch of fabric formed of fibers selected from a group consisting of: nylon, polytetraflouroethylene, polyethylene, polyolefins, polyesters, or polyamides. The envelope assembly 16 is preferably formed as a pouch 20 with a body portion 22, having an inner chamber or compartment 24, and at least one sealed end 26 which is preferably formed by applying heat and pressure to heat seal the end region 30 of the envelope 16 assembly, or by sealing with an adhesive.

The body portion 22 of the assembly 16 has a sidewall formed of the vapor permeable membrane material 18 which surrounds all sides of the chamber 24 to provide passage of air vapor through adjacent and/or opposed sidewall regions, such as is shown with the air flow directional arrow (depicted in the Figures as 28). Thus, the structure of the assembly according to the present invention is configured to provide a chamber 24 containing fill material 32 with vapor-phase corrosion inhibitor compounds, with permeable sidewalls on more than one side of the compartment, and preferably having permeable areas on adjacent or opposed sidewalls. This structure facilitates release of vapor from the chamber 24 to the exterior environment, as the outer membrane 18 has a curvilinear or angular configuration and is not merely flat such as would be the case of prior art containers having a permeable covering of a plastic cup. Further, because the body portion 22 of the assembly 16 is pliable and preferably not rigid, vapor passage thought the membrane 18 is also naturally facilitated by movement of the articles in the package 10 during shipping/handling of the package 10. This structure of the envelope assembly 16 with permeable sidewalls of the pouch 20, in combination with fill material 32 having properties described herein, provides an assembly 14 with vapor passage 25 for improved exchange of vapor from the pouch 20 into the package 10.

The envelope assembly 16 includes fill material 32 made up of a substrate material that is substantially inert to the conditions at normal environmental parameters of room temperature, normal moisture levels, etc., and is not readily friable or frangible into powdered form. The substrate material therefore acts as a stable non-frangible base medium in the range of average environmental conditions. Different substrate material may be utilized, depending on the intended or anticipated conditions associated with a given product 12 or container 10. For example, depending on the sensitivity of the product 12 to extreme conditions of moisture or temperature, and the perceived need for increased exposed surface area of the fill material for use according to this invention, it may be desirable to provide a substrate material that is substantially inert in the range of room temperature (in the range of 21 to 23 degrees Celsius) or some similar quantifiable ambient temperature, at a given environmental pH range, and at a given ambient moisture level and atmospheric pressure. In keeping with an important aspect of the invention, such substrate material, although not entirely inert or stable at all potential environmental conditions, is stable in solid phase at average or ambient environmental conditions. In this manner, therefore, the present invention preferably does not utilize a desciant material as a substrate 36, and instead utilizes a substrate that does not break down or change form solid phase in the presence of ambient moisture.

In the preferred embodiment discussed in detail herein, the substrate material 36 is inert at all typical ambient conditions, and preferably of a material such as plastic resin. The fill material 32 according to the present invention includes a vapor-phase corrosion inhibitor compound material 38 (“VCI compounds”) incorporated into the substrate material 36. The corrosion inhibitor compound material is preferably a combination of different specific VCI compounds, such as the preferred mix of the following compounds: sodium nitrite, sodium benzoate, and benzotriazole. In the preferred embodiment, the mixture of the chemicals that forms the corrosion inhibitor compound material includes a formulation of the following relative components (by weight): at least 11% to 25% Sodium Nitrite, 7% to 15% sodium benzoate, and 2% to 6% benzotriazole. The ratio of substrate to VCI compounds (substrate/compounds) is a significant aspect of the invention. Because the fill material 32 has a large amount of substrate (by volume) relative the corrosion inhibitor compound, the resulting fill 32 has an increased volume and surface area relative prior art devices.

In an embodiment of the present invention, the fill material 32 is formed as a mixture of plastic resin as the substrate or base medium material and a compounded substance having vapor phase corrosion inhibiting properties incorporated into the resin, suitable for emitting the corrosion inhibiting compounds into the atmosphere. One form of this preferred embodiment is depicted as the fill material in the Figures, such as in FIGS. 3 though 5. In this embodiment, the base medium 36 of resin is in the form of pellets 34 of plastic resin 36, such as low density polyethylene, and the corrosion inhibitor compound 38 is incorporated into the resin pellet 34 such that the compound is released from the exposed outer surface 40 of the pellet 34.

This embodiment of the invention, using resin pellets, is advantageous for numerous reasons, including the fact that the embedded compounds removes any need for loose powdered compounds in the envelope assembly 16 because the resin pellet 34 hosts the corrosion inhibitor compound. Also, this embodiment is advantageous because the resin pellets 34 may be universally used as either the fill material 32, or may be extruded into plastic sheet stock with vapor phase corrosion inhibitor properties, as is typical in other applications and for other specific uses. Further, the resin pellets 34 may be used to form into molded medallions or bars, or some other shape that is desirable for a product that is intended to be inserted into packaging material or placed inside a housing of a product. Thus, one aspect of the present invention is to use a predetermined optimal amount of resin pellets, otherwise intended for use in the manufacture of the corrosion inhibitor emitting film, as fill material in envelopes for corrosion inhibitor emitting functions. In the preferred embodiment of this invention, the resin material serving as the base medium 36 comprises approximately 45% to 80% of the pellet 34, and the corrosion inhibiting compounds 38 comprise approximately 55% to 20% of the resin pellet fill material 34. Thus, the ratio of substrate 36 (by volume) to compounds 38 (by volume) has a value greater than 0.75, and preferably not more than approximately 4.0. This may be understood as a ratio of:

$\frac{Vsubstrate}{Vcompunds} = {\left( {0.75 > 4.0} \right).}$

This range of substrate-volume to compound-volume results in an overall fill volume that provides increased surface area and open space for air/vapor flow 25 through the fill material 32. As the pellet 34 is manufactured within this range of composition, a small amount of resin pellet fill material 34 (preferably an amount of approximately 3 grams) may be used to provide sufficient corrosion inhibitor compounds in the vapor within a product package 10 for a package volume of approximately one (1) cubic foot.

The resin pellets 34 are preferably made according to a manufacturing method in which the low density polyethylene resin and the vapor phase corrosion inhibitor compounds are mixed, such that the resin acts as a substrate or base medium for the compounds. The resin and compounds are thoroughly blended in a mixer device, such as a ribbon blender, and the blend is then subject to a compounding process using a mechanical compounding device, such as a single or twin screw extruder. This compounding step is preferably performed at an elevated temperature, in the range of at least approaching the melting point of the resin material. In the case of the base medium constructed of low density polyethylene, the compounding step is performed by an extruder with the mixture being elevated to approximately 350 degrees Farenhiet. Once compounded, the mixture of the resin and compound(s) is cut into the desired length of pellets, as is typical in the industry for use as a source material for sheet stock extrusion, or for molding into a desired shape of corrosion inhibitor emitting block or object.

Alternative embodiments of the present invention includes use of a material other than resin pellets as a base medium. One form of such a product, shown in FIG. 7 utilizes a body of fiberous material 40. The fibers are used to absorb the corrosion inhibiting compounds, which are thereby bound to the fibers, thus a structure in which the fiberous body as the substrate. In a preferred form of this embodiment, a body of compressed and/or woven fiber, such as cellulose fiber pressed into a pad 42, serves as the substrate within the pouch. Although such pads have been used previously as a device inserted or taped directly inside a shipping container 10, the present embodiment provides a surrounding vapor permeable sidewall, useful for isolating the pad and allowing for ease of product labeling. Similar to the resin product described above, the pad 42 of fiber material acts as a carrier substrate 36 for the corrosion inhibitor compound material 38, such as by soaking the pad in a liquid suspension of the compound(s) to have the compounds entrapped into and/or adhere to the fiber web of the pad 42. Depending on the solution of the suspension, the saturated pad either may be dried fully or kept moist, and is then inserted into the vapor-permeable envelope for use as a product package corrosion inhibitor emitting device.

In yet another embodiment of the present invention, as shown in FIG. 6, the envelope assembly 16 contains a fill 32 comprised of ribbons 44 or other segments of sheet stock of corrosion inhibitor emitting material, such as paper impregnated with the compounds and/or plastic film formed of such material as low density polyethylene. The sheet stock may be cut into segments and/or formed into shapes that increases the volume of pile if material, such as by curled ribbon or similar such body shapes, that will provide air space between the sheet stock segments, as shown in FIG. 6. This results in a fill material 32 with air passageway 28 for vapor to be emitted form the envelope 16 to the environment in the package 10.

In another embodiment of the invention, as shown in FIGS. 8 and 9, the fill material 32 is formed as a solid body or block of substrate 36 with embedded or integrated corrosion inhibitor emitting compounds 38. In this form, the pouch 20 is similarly formed as an envelope with a seal 26 at the end portion(s) and a body region 22 has an inner compartment or chamber 24 which contains the fill material 32, shown in FIG. 8 as multiple bodies 32 depicted in FIG. 9. As with other embodiments, spaces within the inner compartment 24 of the pouch 20 exist between the substrate bodies 32, and between the substrate 32 and sidewall 18 of the pouch 20. This structure, along with the vapor permeability of the surrounding sidewall 18, allows for vapor/air passage 28 through the pouch 20. Also, this embodiment is particularly advantageous as an alternative to the plastic resin pellets described above and shown in FIGS. 3-5, as the body of substrate 32 in FIG. 9 may easily be manufactured from the pellets such as shown in FIG. 4 by conventional molding processes. Thus, FIG. 9 embodiment of a molded or otherwise formed resin substrate boy 32 is compatible with, and potential co-existing alternative of, the use of resin pellets, suitable as source material for plastic molding processes, such as shown in FIGS. 3-5.

While the specific embodiments have been illustrated and described, numerous modifications come to mind without significantly departing from the spirit of the invention, and the scope of protection is only limited by the scope of the accompanying Claims. 

1. A corrosion inhibitor assembly for emission of vapor phase corrosion inhibitor compound inserted into a shipping or packaging container, comprising: an outer encasement envelope constructed of sheet stock having vapor porous properties for permitting vapor to pass into and out of the envelope, said envelope being sealed to form an inner chamber with at least a portion of said porous sheet stock configured to provide vapor passage from the chamber; and a combination of a generally inert substrate material with embedded vapor phase corrosion inhibiting compound located within the chamber of the envelope.
 2. The assembly of claim 1, wherein said generally inert substrate material is plastic resin.
 3. The assembly of claim 2 wherein said substrate material comprises pellets of plastic resin and wherein small particles of inhibitor compound are embedded into the plastic resin pellets.
 4. The assembly of claim 3, wherein the vapor phase inhibitor compound resides primarily on the outer surface of said pellets.
 5. The assembly of claim 1, wherein the substrate comprises cellulose.
 6. The assembly of claim 1, wherein the substrate comprises a body of fiberous material.
 7. The assembly of claim 1, wherein the corrosion inhibiting compound comprises a mixture of sodium nitrite, sodium benzoate, and benzotriazole.
 8. The assembly of claim 7, wherein the substrate comprises low density polyethylene resin.
 9. The assembly of claim 2 or 7, wherein the combination of substrate and corrosion inhibiting compound is in the form of polyethylene resin pellets configured for use in manufacturing plastic film.
 10. The assembly of claim 2, wherein the envelope contains approximately 3 grams of the resin substrate with the corrosion inhibiting compound.
 11. A corrosion inhibitor assembly for emission of vapor phase corrosion inhibiting compound, comprising: an outer encasement envelope constructed of vapor porous sheet stock configured to permit vapor to pass through the envelope; and a mixture of substrate material and vapor phase corrosion inhibiting compound material residing inside said envelope, said corrosion inhibiting compound material being incorporated into said substrate such that said mixture is not readily frangible and said inhibiting compound material is configured to emit vapor phase corrosion inhibitor compounds while otherwise being generally inseparable from said substrate.
 12. The assembly of claim 11, wherein said substrate comprises polyethylene resin.
 13. The assembly of claim 12 wherein said substrate material comprises pellets of plastic resin and wherein small particles of inhibitor compound are embedded into the plastic resin pellets.
 14. The assembly of claim 11, wherein the substrate comprises cellulose.
 15. The assembly of claim 11, wherein the substrate comprises a wool of fiberous material.
 16. The assembly of claim 11, wherein the corrosion inhibiting compound comprises a mixture of sodium nitrite, sodium benzoate, and benzotriazole.
 17. The assembly of claim 11, wherein said mixture comprises segments of polyethylene film with corrosion inhibiting compound incorporated into said film.
 18. The assembly of claim 11, wherein the substrate and compound mixture includes waste material from the manufacture of plastic sheet stock of corrosion inhibitor emitting film.
 19. The assembly of claim 11, wherein said substrate is selected form a group of materials comprising cellulose and polyolefin such as polyethylene, poly propylene, and polybutene.
 20. The assembly of claim 11, wherein the substrate and compound mixture comprises a molded body of resin material.
 21. A method of providing corrosion inhibiting compounds in the vapor of a packaging for a product, comprising: providing an encasement envelope constructed of vapor porous sheet stock and having at least one fill opening for receiving a fill material and configured to be sealed; inserting the fill material into said envelope and subsequently sealing said envelope, the fill material comprising a mixture of substrate material and vapor phase corrosion inhibiting compound material incorporated into said substrate such that the mixture is not readily frangible into powder form, said envelope and fill material being configured for placement into a packaging container of a product for the vapor phase corrosion inhibitor being released in the interior environment of the container.
 22. The method of claim 21 further comprising the step of forming a mixture of substrate and corrosion inhibiting compound material by mixing the compound material with a generally inert substrate.
 23. The method of claim 22, wherein said step of forming the mixture includes use of plastic resin for said substrate.
 24. The method of claim 22, wherein said step of forming the mixture includes use of cellulose for said substrate.
 25. The method of claim 21 further comprising the steps of: forming an envelope of vapor porous sheet stock formed of synthetic material and, sealing said envelope by heat and pressure to mold a seal of said synthetic material.
 26. The method of claim 21 wherein the step of inserting the fill material into the envelope is performed with the inclusion of one or more vapor phase inhibitor compound selected from the group consisting of: sodium nitrite, sodium benzoate, and benzotriazole.
 27. The method of claim 26 wherein the step of inserting the fill material into the envelope is performed wherein the fill material includes a corrosion inhibiting compound material includes a formulation of at least 11 to 25% Sodium Nitrite, 7 to 15% sodium benzoate, and 2 to 6% benzotriazole.
 28. The method of claim 21 wherein the step of providing an encasement envelope includes the step of creating a pouch of fabric formed of fibers selected from a group consisting of: polytetraflouroethylene, polyethylene, polyolefins, polyesters, or polyamides.
 29. The method of claim 22 wherein the step of forming a mixture of substrate and corrosion inhibiting compound material by mixing the compound material with a generally inert substrate includes the steps of blending plastic resin with said corrosion inhibiting compound material and extruding the blended resin and compound mixture at an elevated temperature.
 30. The method of claim 29 wherein the step of forming a mixture of substrate and compound material includes the step of extruding low density polyethylene resin.
 31. A pouch of vapor-phase corrosion inhibitor mixture for use as an added item in a packaging container with intended emission of vapor phase corrosion inhibiting compound into the packaging interior environment, comprising: a synthetic outer encasement envelope constructed of vapor porous sheet stock configured to permit vapor to pass through the envelope, said envelope containing a non-frangible and non-friable fill material made of a base medium hosting a corrosion inhibiting compound material that is configured to release vapor-phase corrosion inhibiting compound to the environment surrounding the envelope, wherein the fill material is in the form of a visible solid that is generally absent of visible powder and not readily crushed into a powdered form.
 32. The assembly of claim 31, wherein said base medium comprises at least one body of plastic resin.
 33. The assembly of claim 32 wherein said base medium comprises pellets of low density polyethylene resin with embedded compound material therein.
 34. The assembly of claim 31, wherein the base medium comprises cellulose fiber.
 35. The assembly of claim 31, wherein the base medium comprises a compact body of cellulose fibers with an absorbed content of said inhibiting compound material.
 36. The assembly of claim 31, wherein the corrosion inhibiting compound comprises a mixture of sodium nitrite, sodium benzoate, and benzotriazole.
 37. The assembly of claim 31, wherein said compound and base medium mixture comprises ribbon segments of polyethylene film wherein the corrosion inhibiting compound material is incorporated into said film.
 38. The assembly of claim 31, wherein the mixture of base medium and compound material is formed of waste material from the manufacture of plastic sheet stock of corrosion inhibitor emitting film.
 39. The assembly of claim 31, wherein said base medium is selected form a group of materials consisting of: cellulose or a polyolefin such as polyethylene, polypropylene, and polybutene.
 40. The assembly of claim 31, wherein the mixture of base medium and compound material comprises resin pellets configured for use in the manufacture of extruded vapor-phase inhibitor emitting plastic film. 